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                            CORONARY  ARTERY  DISEASE

                                                         Andrew Ying-Siu Lee, MD,PhD.

       When there are atherosclerosis, spasm, thromboembolism, arteritis, trauma affecting the coronary arteries,  there is coronary artery occlusion so that the insufficient supply of blood and nutrients to the heart may lead to myocardial ischemia or necrosis, known as “coronary artery disease”. 

Types of coronary artery disease include:-

(1) Acute coronary syndomes:

           1. ST elevation myocardial infarction (STEMI)

           2. Non-ST elevation myocardial infarction (NSTEMI = unstable angina + elevated cardiac enzymes)

           3. Unstable angina

(2) Chronic coronary artery disease:

           1. Stable angina pectoris

           2. Prinzmetal (variant) angina

           3. Syndrome X (microvascular angina)

           4. Silent myocardial ischemia

       Signs and symptoms of coronary artery disease include: chest tightness, pain or discomfort which may radiate to left shoulder, left arm, neck, jaw etc., dyspnea, dizziness or fainting, palpitation, nausea, vomiting, cold sweating, weakness, numbness of fingers etc.  Angina equivalent include dyspnea, syncope, weakness, cold sweating etc.   In chronic coronary artery disease, symptoms usually subside in 10 to 15 minutes after rest or sublingual intake of nitroglycerin.  If anginal symptoms severe or persistent (more than half an hour), it may be acute coronary syndromes which include acute myocardial infarction so called "heart attack".  Since acute myocardial infarction is the most severe coronary artery disease and the immediate mortality so high, patients should consult Emergency Department immediately whenever they have persistent or severe chest discomfort, cold sweating, cold extremities, pallor, weakness, diaphoresis etc.

       Risk and precipitaing factors of coronary artery disease include: age, smoking, diabetes mellutis, hyperlipidemia, infection, cardiac arrhythmias, hypertension, anemia, gastrointestinal bleeding, thyroid disease etc.

        Investigation of coronary artery disease include:-

        biochemistry : plasma lipids, glucose, CK, CKMB, troponin, CRP etc.

        electrocardiogram

        exercise electrocardiogram

        myocardial perfusion imaging

        stress echocardiography

        cardiac catheterization

        General measures of coronary artery disease include:-

        - identify and treat the causes (primary or secondary)

        - reduce cardiac risk factors

        - antianginal drugs

        - revascularization by coronary intervention if:

              - ST elevation myocardial infarction

              - high risk patients

              - recurrent angina at rest or minimal exertion associated with electrocardiographic changes

              - hemodynamic instability, heart failure, arrhythmias etc

       Coronary artery disease can be divided into (1) stable angina pectoris (2) unstable angina pectoris and (3) acute myocardial infarction, mortality of which are :-

                                                              In-hospital Mortality        5 year Mortality

1. stable angina                                                    minimal                    5-10%

2. unstable angina                                                      5%                     10-25%

3. acute myocardial infarction                              15-20%                    10-30%

                                                              (additional mortality of

                                                        15-20% before reaching hospital)

       The severity and prognosis of coronary artery disease depend on the risk factors, precipitating factors, degree of coronary artery occlusion, heart function, body fitness, symptoms and signs, complications etc.  Complications of coronary artery disease include: cardiogenic shock, heart failure, pulmonary edema, cardiac arrhythmias, pericarditis, pericardial effusion, thromboembolism, hemodynamic disturbances etc.  Therefore, aside from correct diagnosis, the exploration and therapy of above conditions is also important.

       The therapy of coronary artery disease include: (1) medical therapy, (2) coronary intervention, (3) surgery, (4) cardiac rehabilitation, (5) preventive measures and (6) recent research.  Successful treatment of coronary artery disease can lessen the severity of coronary artery disease, improve heart function, attenuate symptoms, and improve life quality of patients.  On the other hand, merely symptomatic treatment of coronary artery disease can only relieve symptoms, but heart function and prognosis continue to worsen, leading to end stage heart disease.

       “Coronary artery disease is not trivial disease, heart attack is killing !”  Therefore, all patients with stable or unstable angina should have regular treatment and follow up.  For patient with myocardial infarction, they should have therapy for life.  Coronary artery disease patients should have good compliance, regular medical treatment, regular examination, avoid risk and precipitating factors such as smoking, diet control, regular exercise, emotional control, body fitness, control hypertension, control infection etc.